My drawings are available (P-61, B-17 & Short Sunderland plans updated in 2010). The A-26B Invader plan is available now; 28 March 2017; (see Downloads or Contact-Plans-Links)

But from the B-17 only the smaller version 1/10th of 1983 (spw 3,16m).

For my 1/8th version I have cut out the necessary parts from my own 1/10th plan and copied them 125%, and have adapted the constructions a little bit for a fuselage-splitting, and extra wing-splittings.

In relation to the transport and the handiness, the tailsection had to be detachable, and therefore providings were attached for the Fuselage-Tailsection joining and glued into some formers. At the joining so a Dualformer (Sandwich:2x 1mm ply with inbetween them 6mm balsa with plywood rings, the outer ply rings not glued on yet, later after planking !!), is bolted together with four socket bolts and blind nuts M4, (2mm balsa strips between them, this for the later on two outersides glued 1mm ply rings. These as completing the sandwich Dualformers, and as

protection against damaging the balsa sheeting, and for a perfect seamfitting of the fuselage parts).

The fuselage-joiner itself can be very light: flat springwire 6x1mm in flat brass tubes 7x2mm. The flat brass tubes are provisional in one piece and on both sides, glued in 2 formers (front- and tailpiece must be sheeted apart), and later, after planking and the bolts have been removed, sawn through between the the dual formers (perfect fitting). Now the the outer 1mm ply rings can be glued to the Dualformers, to finish these as a Sandwich.

Fuselage-Tail Splitting Short Sunderland

Fuselage-Tail Splitting B-17

Fuselage-Tail Splitting B-17 (detail)

Tail-Boom Splitting P-61 Black Widow

Fuselage-Tail Splitting A-26B Invader

Steering Rods:

In the B-17 & Short Sunderland, all the Fuselage-servos are in the front of the nose (to avoid a lot of extra lead) and all linkages to the rudders are a closed-loop system (plastified control line wire), these linkages had to be disconnectable on the spot of the fuselage splitting.

On a 3mm ply strip, in the front of the tailpiece, there are 3 cranks (3mm axle), which all are connected with kwiklinks and a closed-loop system to the inner control horns of rudder and elevator. On these 3 cranks there are also, all on the outside, threaded ball links (M2).

The connection forwards take place with alu. ball links and and moved on security clips, naturaly also with a closed-loop system to the servo’s.

The kwiklinks on the servo’s have to be disconnected every time!

In the P-61 & A-26, the servos for rudder and elevators are as far as possible forwards in the tailsection (In the P-61 for both booms!).

Linkage-Splitting Short Sunderland.

Linkage-Splitting B-17 just like the Sunderland.

Linkages-Splitting B-17 (servo’s all in the front of the nose!)

P-61 Elevator & Rudderservos (upsidedown) in the front of the Tailplane.

P-61 Elevator & Rudderservos (upsidedown) in the front of the Tailplane.

Linkages of elevators & rudder in A-26B Invader.

STABILIZER- and WING JOINERS:

Stabilizer joining:

Short Sunderland;

-On the Sunderland the stabilizer has been glued, in one piece, into the Tailplane. The elevators are direct linked, internal via 2 apart built in cranked pianowires (3mm bended pianowire, bearinged in plastic tubes) with control horns. The elevators they have glued in tight fitted plastic tubes, and are slided over these cranked pianowires, not glued, so they are always removeable. So also the rudder.

Stabilizer Sunderland, in one piece (elevators and rudder are removeable)

B-17 Flying Fortress, P-61 Black Widow & A-26B Invader;

-On the B-17 & A-26B, the stabilizer is in 2 halves, removeable and joined to the fuselage with carbon tubes Ø 11mm

(1/10th B-17 carbon tube Ø 9mm; in updated drawing in 2010!).

-On the P-61 the Stabilizer is removeable between both booms and joined to the booms with carbon tubes Ø 9mm.

The elevator linkage control is provided, by both, in the moment that the Stabilizers have been slided against the fuselage or boom.

Solution for these 3 models:

Square brass tubes sliding in each other (5mm in 6mm). The 5mm tubes in the elevators are provided with 1mm brass strips for more gluesurface against 2 ribs.

The brass tubes in the fuselage are splitted in a left and and right part (separated linkage for also here each an own servo),on the outer ends on the tubes are soldered small pieces round brass tube, and bearinged in paxolin strips. Each halve has so his own control horn for a separated linkage.

The P-61 however, has only one stabilizer with a single elevator, but is yet linkaged to 2 servo’s, in each boom 1 elevator-servo. (8kg servo’s, but currentless to move with one finger!! In case one fails, it should not be a problem for the other servo, pulling this around too).

Left Stabilizer-part B-17

Stabilizer P-61 with carbon join tubes

Stabilizer P-61 with the elevator control tubes (so also B-17)

Elevator- and rudder linkage on the P-61.

A-26B Invader Stabilizer Joiners.

A-26B Invader Elevator linkages.

Wing Joining:

-On the 1/8th B-17 the wing consists of 2 halves , which are slided to the fuselage with wingjoiners. The wing joiner on the front is a loose thinwall Dural tube Ø30mm and the rear a Ø18mm one. (Each winghalve on the 1/8th B-17 is also divisible in 2 parts ). (For the 1/10th B-17 drawing I have updated it in 2010 with a loose thinwall dural tube Ø 25mm and carbon tube Ø 11mm).

-On the P-61 & A-26B, the wing is also in 2 halves, the wing joining is the same as on the B-17, but now with dural tubes Ø35 and Ø20mm. ( Each winghalve on the P-61 & A-26B is also divisible in 2 parts .)

These tubes are thus loose and in a single piece and slided into fiberglass guide tubes (glued in to the fuselage and innerwing halves).

The wings, also provided with guide tubes, are slided over the stretched out tubes and secured with long “Parkers”, through abachi blocks (glued on the guide tubes) into the tubes, which are

provided internally with short and small ash-wood or hickory blocks (on her sides and so making the tubes even stronger against nodding).

Winghalve B-17 (innner & outer part)

Winghalve P-61 (inner & outer part)

Winghalve A-26B (inner & outer part)

-Each winghalve on the 1/8th B-17 , P-61 & A-26B is also divisible in 2 parts and also these are connected with wingjoiners, but now glued in, and not loose in one piece.

The outer wingparts;

On the B-17: in front a Ø18mm dural tube and the rear one a Ø11mm carbon tube.

On the P-61 & A-26B: in front a Ø25mm dural tube and at the rear Ø11mm carbon tube.

The innerwing parts have on the outside, glued in, polyester guide tubes.

On the spot of the deviding there is of course a dual wingrib (for each part, one) and during the open construction, the joining has to been attached, this for an accurate fitting! The security is done, as with the fuselage-wingjoiners, with “parkers through abbachi blocks into the tubes, internally also provided with ash-wood or hickory blocks. The stabilizer joining with the fuselage consists of glued in carbon tubes Ø11mm, forward and rear, which are slided into polyester guide tubes glued in the fuselage. Here also the security is done with “parkers”.

Splitted Winghalve 1/8th B-17

Dural and Carbon Wing & Stabizer Joiners

Outer Winghalve P-61

P-61 Inner Winghalve with Nacelle + Outer Winghalve.

A-26B Inner left Winghalve with partly the Nacelle.

A-26B Inner right Winghalve with Nacelle.

-At the Sunderland the wing only consists of 2 parts (stabilizer glued on), which are connected with each other by a wingjoiner of flat springsteel 1,5x15mm in a gluedin brass flat tubes 2,5x16mm, forward with 2 of them above each other, a long one untill the First nacelle and a short one. The rear is a short one 1,5x12mm in a brass tube 2,5x13mm.

The Winghalves for the Sunderland are secured to each other with 2 alu. strips and parkers in abachi blocks, and than bolted on the fuselage with 4 long stainless steel bolts M6, in to the fuselage fixed metal inserts.

Over this than comes the long cockpithood, which stretch from nose to the rearend of the wing.

The real B-17 has splitflaps and on the model these were built directly against the wing underside, with clearfoil between it as a barrier.

The special flap hinges were attached, recessed into the flaps and wing under-surface. There is a gap between wing and under-surface when these are lowered, giving more lift and less drag!

The flaps are controlled with internaly M2,5 rods., and because of their huge surface linkaged to an 8kg servo.

With the computer transmitter these servo’s were slow downed to 5 sec., so that the nose does not go up, because the model has so the time to adapt itself to the flap situation, every moment!

Splitflaps B-17 (still to construct against the wing!)

Splitflaps B-17

Short Sunderland Fowler Flaps:

This are Flaps moving simultaneous backwards and downwards, giving a lot of more lift in slow flying or allowing even a more slower landing.

At the Sunderland model that had to be max. 9 cm backwards and 40° downwards!

But how to make this complicated system practicable for a model?

The end result looks very simple and finally it is so! But before that it was a long way to go. A lot of experiments, hours! For certain, because the Flaps have a trapezium shape, so the travelway is on each outerside different, and adjusting of them did require a lot of time.

The Flap itself was constructed again, with clearfoil between it, against the hollow underside of the rear wingedge. Also here, each Flap is linkaged to an 8kg servo, and for the same reason as at the B-17, slowed down to 5 sec.

From the servo there goes a rod (M3 with ballinks) to both sides of each flap to large cranks. From these cranks there are leaving 2 rods, both connected on the same side of the crank. One (the outer one; M2 rod with kwiklinks) for the there and back movement. To this rod there (beared in hardwood blocks provided with a piece of plastic tube) the Flap is connected, hinge jointed,. The second rod (the inner one; M3 rod with ballink and kwiklink) goes from the crank straight to the control horn of the Flap (the Up and Down movement).

Drawing; linkage Fowler Flaps Sunderland

How does it operates than?

Because the inner rod on the crank makes a shorter stroke than the outer one, the inner one really holds up the flap during the slide-movement,

so that the flap starts to turn over on his hinge-joint on the leading edge. The more larger sliding movement, the more turnover movement!

The extent of the turnover movement defines thus the angle of which the flap gets lowered and is thus dependent from the distance differance between the two side by side seated rods on the crank!

After a severe waterdamage, by a hole in the hull (an under water hidden boulder), the condition of the balsawood rapid declined, andat one point it wasnotjustifiedto fly any longerwiththe model.

Fowler Flaps Short Sunderland (upperside)

Fowler Flaps Short Sunderland (underside)

P-61 Flaps and Spoillerons:

The P-61 had conventional slotted Flaps (Not the ZAP Flap as described in some articles or books! These were only on the prototype XP-61 !). They can be lowered max. 60º, and are as well at the inner- as at the outerwing section, so total 4. The special flaphinges are recessed into flap- and wing undersurface. Again there is a gap between wing undersurface and flaps, when these are lowered, giving more lift and less drag! They are linkaged with M2,5 rods and kwiklinks and controlled by 8kg servo’s, and again slowed down to 5 sec.

The spoilerons are laminated, in a halfround and tapered moulding, of 3 sheets 0,4 ply, and between them carboncloth + epoxy.

They are hinged (almost at the rear, on the upperinside of the the outerwing), on a long 3mm pianowire in a plastic tube, so it can turn out of the wing (therefore in the ribs are sawed segment shaped slots), and is eccentrically controlled direct from a servo, turning up simultaneous with the small tip aileron on the same side. On the other wing the tip aileron is going down of course, but the spoileron remains, almost unmoved, inside the wing (on account of the eccentric control linkage).

Flaps P-61 (on inner- and outerwing) + spoileron & tiny tipailleron

Spoilleroninkage P-61

Spoilleron + tiny tipailleron P-61

A-26B Invader Flaps: The A-26B Flaps had Double-slotted Fowler Flaps, but for the model it was to complicated to make it scale! So I made normal Fowler Flaps (but the linkage is different as it is in the Short Sunderland model). These Fowler Flaps are going backwards max. 50mm en max. 50° downwards. An 8 kg servo (again slowed down to 5 sec.) controls a long 4mm pianowire via a controlhorn in the middle, on this axle, there are 2 more controlhorns and these are controlling 2 pushrods (through long guiding tubes), inked on the upperside of the Flap-leading edges. On the same controlhorns there are M3 rods, but a little bit closer to the axle and linked on the underside of the Flap-leading edges. On one outerside of the flaps there is a third rod (also through along guiding tube), but not controlled, just for extra guiding! Because these M3 rods are controlled closer to the axle, they make a shorter way than the upper pushrods, and so the Flaps are turned over, more and more, during pushing. Very simple, but adjusting the whole, took a lot of time, because the flaps are not rectangular but tapered! So the push-movement is on both outersides different!

Fowler Flaps A-26B Invader.

Flap-linkage A-26B (innerFlap)

Flap-linkages A-26B (upperside)

Flap-linkages A-26B (underside)

COWLINGS, MOTOR-DUMMIES, TURRETS, etc.

Cowlings Short Sunderland & B-17:

These have all over, the same cilindric dimensions.For theShort Sunderland & 1/10th B-17 ; Ø150mm (6"), and for the 1/8th B-17 ; Ø180mm (7").

Therefore these can be made from aluminium stove- or flue pipes(available in many diameters), the rounded nose cowlring can be made

from GRP, with the so called balloon method(see further on!). A plywood ring has been glued half into the pipe, on this the self formed GRP ring can be glued. For this ring you have to make a wooden mould, like the other moulds(3m ply bottom + some 3mm ply cross-sections + filling with balsa,

and than planing and sanding). But first there can be glued a motor-dummy to the plywood ring!

Short Sunderland Alum. Cowling with GRP nose cowl-ring.

B-17 Alum. Cowling with GRP nose-ring.

Mouldings & Plugs for the Short Sunderland

Mouldings & Plugs for the 1/8th B-17

Balloon method.

Glue to the mould a Block or a attach a pin and jam this in a vice, and so, that the mould is free well! The mould has been covered with clearfoil (less fouldings as possible), which is secured with sellotape.

Over itcomes a 80grams, or heavier,open wave mat. The whole iscoated withpolyester orepoxyfast-acting(10 min). Over this isloosely(less wrinkles as possible) a clearfoilagain. The startof hardening, (keep an eye on aresiduein the potvery well), it begins after about10 minutes. In themeantime, inflate averylargepartyballoon(For sale in afestivearticleshop, uninflated upto 50cmdiameter available. AdviceSize: Balloondiameter not inflated;2.0 to2,5xmoulddiameter, the larger ones to inflate with abicycle pumporcompressor).

This inflatedballoon iskept readyjustbefore thehardening process, together with a potential balsainner ring(for forming a leading edge in certaintypes ofcowlings) pushed against the front of the mould. Continue pressing, andlet escape some air at the same time, untilthe balloon isat the backofthe mould. Keeptensionon the balloonandkeepthetrunk of theballoontightlysqueezed, and keep the balloon pressed over the mould with your arms. Thisis whynot immediatelythe balloon is going to be pressed againstthe mould, because thenyou stand there, after at least 15 minutes, withanaching back! After the start ofhardening, the balloon andthe outer clearfoil can be removedandthenlet ithardenproperly. Thentheexterior can be sanded wet withwaterproof sandpaper, cutoffthe foldedback, slide the product ofthe mouldandremovethe inner clearfoil.

Thesearenotthe samediameterover its entire length, so the methode for the Sunderland & B-17could not be used(aluminium stove- or flue pipe with a GRP nose cowl-ring). Thereforeapositivewooden mould have to bemade first​​(with 3mm plywoodbottom former + some cross-sections andbetweenthem balsa blocks, than planingandsanding it in shape). Then thecowlings(largestdiameterØ210mm) were made​​entirelyof GRPwithmyballoonmethod above.

P-61 Mouldings & Plugs for Cowlings, Cockpit, etc.

GRP Cowling P-61 with radial Dummy

A-26 Mouldings & Plugs for Cowlings, Cockpit, etc.

GRP Cowling A-26 with radial Dummy

Radial Dummy Engines; These canbemade yourself​​of plastic(hollow), orpolyurethane foam(solid). Firstmakeapositivemouldwithbalsaparts, to glue on a plywood base, make anegativeprint of this inatrayform resin orplaster.

Sometimes you can buy them, also for some purchased plans, butcertainlynot for your owndesigns! To make them our own, one must first produceapositivemould or plug(3mm plywood bottom former + some ply cross-sections andbetween them balsafilling,than planing, sanding it in shape,andfor avacuummethod finishing it with 25gramsmat andG4 polyurethane). For thevacuummethod one cancontacthobby stores, some of them have the equipment to do this. I myself apply the 20 yearsago myself developed Kitchen ovenmethod.

Kitchen ovenmethode:

Bondto the plug, a block asaspoolhandle.Then make an increasedframeworkof6 to10mmplywood, make an opening, 1mm aroundlarger than thebasic shapeof the plug, place over this acockpitsappropriate0.5 to1 mmthick plasticplate (clear PVC or Buyrate), tighted around, and place it in thekitchenoven(± 200° C). Keep an eye oneverythingandgoodasthe plasticbeginsto sag, take out the wholequickly from theoven and push the plug through it, untiljust belowthe edge ofthe baseplate. Immediatelycool off withadampcloth, so that the materialshrinkstightly overthe plug. One cantakethe product fromthe plugwithsharp scissorsandcut it to size.

Tail Turret Short Sunderland

Nose Turret Short Sunderland

Chin, Sperry Ball Turret, and Tail Turret ofthe B-17, the TopTurretand Nosedomeof the P-61& A-26B werealsoformedwith GRPon positivemoulds, againstwhich the largeballoonwas pushedagain, as defined by the nosering of thecowlings. For theroundSperry Ball Turretof the B-17, I have used the cup ofone of my manytrophiesas a template! (just the right size).

TheSunderlandwasaflying boatand not an amphibianaircraft, so itreallydoes nothave an under-carriage for take-offs and landingson land! Theoriginalcould onlybe provided with aso-called beachinggear for maintenance on land. Icopiedthisscaletobe able to startonland, butspring Oleo's, also thetailwheelthingis scale, from thisthe original was towed out ofthe water. Thebeachinggearcaneasilybeexpandedto a wider track, bypulling out both sides, otherwise it istoo narrowfor land take-offs. For water-flying it is removable, by pulling it out of

thestainless steeltubes from both sides, which are going across through thehull.

The microswitchesarepressed downby adjustablerods,which in their turnarepressedbythespindleback- and forwardmoving part. Thus,the up- anddownstrokecanbe setinany desiredposition. The whole isjointlycontrolledandreversedbyone thirdand doublemicroswitch in the fuselage (for example from Graupner, which fits on a servo).In the B-17arethe struts(with6½”wheels) retracted forwards withthe wheelsfor1/3 part strechted out, just likethe original. Above themlies,ona1mmplywood bottom, the tanks forthe inner engines. The scissorsconstruction isworkingandthereforehard soldered. Thestrutin themiddle is telescopicin the originalplane and retracts the gear. At themodel these strutsaredummies ofbrass, but the middle one is also telescopic.

Own constructed electric Retract B-17, with 6½” wheel

Own constructed electric Retract B-17, down.

Atthe P-61, the nosestrut(with4½”wheel) is retracted backwards, which is also closing the welldoors. In thelowered position, the welldoorsare kept open by self curvedspringsfrom 0.4mmpiano wire. The mainlegs (with7”wheels)arealso retracted backwards, anddisappearentirely in thewheelwells, whosewheelwelldoors exists of 3 parts; twomaindoors thatalso are closed whenthe landing gear is downwards(bythe strutsthemselves viasteelcables),andasmall wheel welldoor next to thewheelstrut,which remains open.

During retracting the gear, all doors, 5secondsdelayed,get closed bytwo180°Servos.

Own constructed electric Retract P-61

The own constructed Retracts with plastic cogwheels as a gear

The plastic cogwheelsas a gear, on the insideof the head wall(B-17), was exchanged later onthe P-61 byagearboxdirectlyto6V. speed 400 motor, because herewasthepressure goingtowardsthe same head wall. (Struts on B-17 are retracted forwards, and on theP-61 backwards, andherewas somepressurethan ontheplastic cogwheels, wheretheycouldnot stand it!)

At the P-61, the plastic gear has been exchanged now for a gearbox

P-61; the 180º Servo for the mainwheel well doors

Main Strut P-61 with 7” wheel

Nose Strut P-61 with 4½” wheel

Atthe A-26, the nosestrut(with5½”wheel) is retracted backwards, which is also closing the welldoors. In thelowered position, the welldoorsare kept open by self bended springs from 0.4mmpiano wire. The mainlegs (with7”wheels)arealso retracted backwards, anddisappearentirely in thewheelwells, whosewheelwelldoors exists of 2 parts,which remains open.

During retracting the gear, all main-geardoors, 5secondsdelayed,get closed by180°Servos.

onthe servo(in the center) and control cables(sullivan) to the 2throttle horns.

For a bettertaxi - take-off and /orplaning on the water, the engines,leftand right, have been mixed withthe rudder, althoughsynchronization of theRPM in flightis not critical, but yes theSunderland onthe water andespeciallyduring planing when the model is on his step!

Andthe B-17is,due toits enormoustail finin the start, with the wind is in an angle or cross, will rapidlybreak out to the wind direction. Evenatthe P-61 & A-26Bthis mixer is programmed, buthas neverbeen necessary, due to the existingnose wheelhere.

Controlling thethrottleshappens hereon both sideswithcontrol cablesofsullivan, linkaged to a servo.

Mixing Rudder / Engines, B17 - Sunderland – P-61 & A-26B:

For thisweneed4mixers, of which mixer2-3-4are on the sameswitch!(at my transmitter a switch on the throttle stick).